Automatic temperature control apparatus



Dec. 29, 1936. F. F. UEHLING 2,065,841

AUTOMATIC TEMPERATURE CONTROL APPARATUS Original Filed June 29, 1932 I5 Sheets-Sheet l 6 V ,J 7 8' 25 22 9 4 INVENTOR y A x A hx m I -1M a EH4 7 .42

2 3 Sheets-Sheet 2 Dec. 29, 1936. F. F. UEHLING AUTOMATIC TEMPERATURE CONTROL APPARATUS Original Filed June 29, 193

Dec. 29, 1936. UEHUNG 2,065,841

AUTOMATIC TEMPERATURE CONTROL APPARATUS Original Filed June 29, 1932 3 Sheets-Sheet 3 940 aJaC/u/ Patented Deena, 1936 PATENT OFFICE AUTOMATIC CONTRQL APPARATUS Fritz Frederick Uehling, Passaic, N., J., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation-of Delaware Application June 29, 1932, Serial No. 619,841

Renewed May 7, 191 16 26 Claims. (01. 236- 91) 1 This invention relates to automatic means for regulating the temperature in a building or in any other housing or chamber. More particularly it relates to improvements in that type of temperature regulating apparatus which depends for its functioning on changes in outside atmospheric conditions rather than on changes in the temperature within the building itself. The invention therefore provides a novel means for changing the rate of heat input to a building in proportion to changes in atmospheric conditions outside the building. In the Particular form of the invention herein described, a valve, through which steam heat is supplied to a building, is

automatically kept open a longer period of time Y and closed a shorter period of time, or kept closed a longer period of time and open a shorter period of time, depending respectively on whether the atmospheric temperature outside of the building has decreased or increased, thus automatically changing the ratio of the valves open period to the valves closed period as required to maintain the desired temperature in the building.

Figure 1 illustrates, partly in cross section and partly diagrammatically; all of the more essen- 1 tie] elements of the'invention; Figure 2 illustrates a deflniteposition of a relay which relay is also shown in Figure l in the opposite position; Figures 3 and 4 illustrate a mercurial thermometer with electric contact points, with respect to' which the mercury of the thermometer is in adifferent position in each figure, said mercurial thermometer being also included in Figure 1;

Figure 5 is an elevation illustrating a. means for changing the quantity of liquid in the vessel I of Figure 1; Figure 6 illustrates a building to which the temperature regulator is applied; Figures 7 and 8 illustrate certain heating and coolin: curves which are of importance in simplifying the description of the novel features of the invention. Similar numerals refer to similar parts in all illustrations.

A vessel I, Figure 1, contains a liquid 2 which liquid is heated by an electric heater 3. The cir- 5 cult which'energizes the heater and which includes a battery or any other source II, .is open or closed depending upon the position of an arm 1 which forms part of a relay suspported by a base 21, which base also acts as a cover for the 50 vessel I. An electro-magnet ll whichforms part of the relay is fastened to the base 21. The arm .1 which is pivoted at 20 is held by a support I! which support is fastened to but insulated fromthe base 31. Contact pieces 6 and 52 are fas-' 55 tened to-ohe end-of the arm-1 and make contact with contact piece 8 or contact piece I8 respectively depending upon whether the magnet is energized or deenergized. The contact piece it is supported by an upright l1 which is fastened to but insulated from the base 31. Similarly the a contact piece 8 isfastened to an upright-9 which is also fastened to but insulated from the base 31. A\spring 24, one end of which is fastened to extension 23 and the other end of which is fastened to the arm I as illustrated, holds the con- 10 tact piece52 against the contact piece I8, Figure 2, when themagnet I0 is deenergized. A contact piece 25, Figure l, is fastened to the other end of the arm 1, as illustrated, said contact piece making electric contact with a flat spring 25 when the magnet is energized. This spring is fastened to an upright 21 which is attached to but insulated from the base 31. It thus follows, Figure 1, that when the magnet I0 is energized, electric contact will be established between 6 and I, and 20 between 25 and 26. Similarly when the magnet I0 is deenergized, Figure 2, electric contact will be established between 52 and I8, and electric contact between 25 and 26, and between 6 and I will be broken. 25

The circuit which includes the heater 3 starts at battery II, from battery ll through wire I2 to the upper end of a rod 5, thence through 1 5 and the heater 3 to a rod 4, from the rod 4 through wire l3 to an adjustable rheostat ll, 30 from the rheostat through wire ii to a rod II, and from the rod 16 through the upright I1 to the contact piece It. When the magnet II is deenergized, the contact piece 52, Figure 2, will touch the contact piece l8 thereby closing the 35 circuit which continues from the contact piece i8 through the arm 1 and wires 2| and 22 back to the battery, Figure 1. It thus follows that when the magnet I0 is energized, the heater 2 will be deenergized, and when the magnet ll 40 is deenergized the heater 3 will be energized. The heater 3 is supported by the rods l, I, and ii. The rods 5 and it are fastened to but insulatedfrom the base 31 while-the rods 4- and i6 are insulated from each other by an insulation piece 5|. The rheostat l4 which-is included in the heater circuit forms a very important part of this invention and will be presently referred to in further detail.

A mercurial thermfmeter 40, Figure l, which has three contact wires l4, l5, and 46, is sealed into a tube 42 at 4!. The tube 42 is fastened to the base 31 at "thereby holding the thermometer in place, as illustrated. The contact wires N, 45, and 46 are sealed into the stem of the 66' thermometer to permit electric contact with the mercury in the stem at predetermined temperatures of the liquid 2. The electric circuits which include the mercury in the thermometer and the and 45 through wires 2|, 49, and 58. The magnet contact wires 44 and 45 also include the magnet l8 and the battery ll. Thus itthe temperature of the liquid 2 is such that the mercury in the thermometer just touches the contact wire 44, Figure 3, the magnet ill will be energized. The circuit which includes the contact wire 44 and the magnet III starts at battery ll, Figure l, thence through wires l2 and 4'! to the magnet II), from the magnet I!) through the wire 48 to the contact wire 45, from the contact wire 46 through the mercury to the contact wire 44, Figure 3, and

thence, Figure 1, through-wires 48 and 22 back to the battery. The magnet lllbeing thus energized, Figure 1, contact will be broken between i8 and 52 thereby deenergizing the heater 8 which will permit the liquid 2 to cool and cause the mercury column in the thermometer 48 to drop. In

this position of the arm I, as illustrated in Flgure 1, the contact established between 25 and 26 will however short-circuit the contact wires 44 I8 willtherefore rem'ain energized until the temperature'of the liquid 2 reaches a point where the electric contact between the mercury in the thermometer and the contact wire 45 will be 30 broken, Figure 4. When this happens the magnet III will be deenergized and by means, of the spring 24, the arm 1 of the relay will assume the position illustrated in Figure 2, thereby again "closing the circuit through the heater 8 by the established contact between 52 and I8, and at the same time breaking the electric connection to the contact wire 45 through 25 and 26. The heater will thus again raise the temperature of the liquid 2 until the mercury reaches the contact wire'44, Figure 3, at which time the cycle 40 will repeat itself. It is obvious therefore that the liquid 2 will cool until the mercury in the thermometer drops to a point slightly below the contact wire 45 at which time the magnet I0 is dee'nergizedv thereby closing the circuit through the heater 8. The temperature of the liquid 2 will then be increased until the mercury reaches the contact wire 44 at which time the relay will again open the circuit through the heater thereby permitting the liquid to again cool. It thus fol- 50 lows that the heater 8 will be energized for a sufilcient length of time only to raise the temperature of the liquid sufliciently to cause the mercury to expand from the contact wire 45, to the contact wire 44 at which time the relay will be actuated to open the circuit through the heater thereby allowing the. liquid to cool only until the mercury drops below the contact wire 45 at which time, in the manner previously stated, ,the heater will be energized again. It is therefore obvious that the temperature of the liquid will continue to fluctuate between a fixed high temperature and a fixed low temperature indefinitely, said high and low temperatures being determined by the fixed positions of the contact wires 44 and 45. It is further obvious that the time required to increase thetemperature sufliciently to cause the mercury to rise from the contact wire 45 to the contact wire 44, and that the time required to permit the liquid to radiate sufiiciently to cause 7 the mercury to drop from the contact wire 44 to 45 will depend upon the temperature of the atmospheresurrounding the vessel I, and the. rate s of heat input through the heater 8.

The relay which energizes or deenergizes the heater 8, depending upon whether the magnet l8 is deenergized orenergized, also respectively opens or closes a motor operated valve 88,-Figure 1. This valve is actuated by a motor 88 which is in geared connection with the valve stem 82 through a gear box 8|. The motor 80 operates to open or close the valve depending upon whether the motor is energized through wires 28 and 85 or through wires 28 and 28. The energy which operates the motor 80 also comes from the battery II. The circuit which actuates the motor to close the valve 88 when the relay is in the position illustrated in Figure 1 starts at battery H, thence through wires l2 and 28 to the motor 80, from the motor 88 through wire 28 to the upright 8 and thence through contact pieces 8 and 5, arm I and wires 2| and 22 back to the battery. Similarly the circuit which'actuates the motor to open the valve 88 when the relay is in the position illustrated in Figure 2 starts at bat tery H, Figure 1, thence through wires l2 and 28-] to the motor 88, from the motor 80 through wire 85 to contact piece l8, Figure 2, from contact piece I 8 through contact piece 52, arm 1, and wires 2| and 22 back to the battery, Figure 1. The valve 88' will therefore be open during the period of time that the heater 8 is energized and closed during the period of time that the heater v8 is deenergized, this cycle repeating itself indefinitely in the manner previously described. It thus follows that the valve 88 will be open for the period of time which is required by the heater to heat the liquid 2 'sufliciently to raise the mercury column from the contact wire 45 to the contact wire 44, and that the valve will be closed for the period of time which is required for the liquid 2 to radiate sufiiciently to cause the mercury to drop from the contact wire 44 to the contact wire 45. I

As already stated, the primary object of the invention is toincrease or decrease the heat input to a building in proportion to changes in atmosph'eric conditions outside of the building in orderto provide uniform temperature within the building. The building, Figure 6, which illustrates this application has its basement divided into three compartments, the chief edgineers ofllce 68, the engine room 8| and the boiler room 82. Ihe motor operated valve 88 w ch may be located anywhere, for example 0 the top floor.

opens and closes the steam flow to any number of radiators 68 located throughout the building. The radiators are connected with the outlet side of the valve through the pipe 84 while the inlet I side of the valve. is connected with a steam boiler- 58 or with any other source of steam supply through thepipe 85. The vessel I which conis preferably located on the-top of the building,

tains the liquid heated by the heater 8, Figure 1,

Figure 6, where changes in outside temperature,

and changes in wind velocity will change the rate of heat radiation from the liquid in the vessel}, In order to protect thevessel against rain and snow, a hood 881s provided as illustrated. The hood is. fastened to a cover 88, Figure 1, which cover protects the relay already is located on top of the vessel it is,obviou's that it maybe provided as a separate unit located anywhere but connected in the manner already described The two wires l8 and I5, Figure 1, which connect rheostat l4 (to be later referred to) are represented inFigure 6 by a two-wire cable 68, and the three wires 28, 2a and a, Figure 1, are represented in Figure 6 by a threewire cable 81.

05' referred to. Although in the illustration the relay In order to adequately describe the functioning of this apparatus, let us assume as already stated that the vessel l is located on the top of the building as illustrated in Figure 6 and that the thermometer 40 which is located in the liquid has its contact wires 4! and 45 located at points respectively corresponding to '75 degreesFahrenheit and degrees Fahrenheit. Under these conditions and in the manner already described, the liquid in the vessel I, is automatically heated by the heater 3 until the temperature of the liquid reaches 75 degrees, then allowed to cool by radiation until the temperature of the liquid drops to 65 degrees, the cycle repeating itself indefinitely so long as the heating capacity of the heater 3 is suflicient to heat the liquid in the vessel I to '75 degrees, and so long as the atmospheric temperature is sufllciently low to permit the heat in the liquid to radiate until its temperature drops below- 65 degrees. Furthermore, in the manner already described, the valve tfi will be open during the period in which the liquid in the vessel is being heated from 65 degrees to '75 degrees, and closed during the period in which the liquid is cooling from '75 degrees to 65 degrees.

The curve 86, Figure 7, represents a heating curve for the liquid in the vessel 1 by plotting temperature against time as illustrated, with the assumption that the heater 3 has suflicient capacity to heat the liquid in the vessel sixty degrees above the temperature of its surrounding atmosphere. For example, the liquid is capable of being heated from 15 degrees Fahrenheit to '75 degrees Fahrenheit when the temperature of the atmosphere surrounding the vessel is 15 degrees Fahrenheit. This is illustrated by curve 80, Figure '7, with respect to the temperature scale V. It is obvious that the curve 85 will have the same general form for any particular temperature of the atmosphere surrounding the vessel. As further examples, if the temperature of the atmosphere surrounding the vessel is 30 degrees the curve 80, Figure '7, will apply with respect to the temperature scale W. Again if the temperature of the surrounding atmosphere is 45 degrees the curve will apply with respect to the temperature scale x, and if the tempera ture of the surroundin tmosphere is 60 degrees the same curve, Figure '7, will apply with respect to scale Ya In other words, the curve will apply for any atmospheric condition so long as the initial temperature line a, column L, represents the atmospheric temperature, and each consecutive temperature line b, c, d, etc. represents an increase of five degrees in the temperature of the liquid.

z W when the temperature 01' the the,

It thus follows that if the temperature of the atmosphere surrounding vessel I is 15 degrees, the

curve 80, Figure '2, between the temperature line a and the temperature line m, column L, will determine with respect to the temperature scale V, the time required to heat the liquid from 15 degrees to degrees, and similarly that part of the curve between the line -k and the line m with respect to the same temperature scale V. will determine the time required to heat the liquid from 65 degrees to '75 degrees, when the temperature of the surrounding atmosphere is 15 degrees Fahrenheit. In like manner that part of the curve 8@ between the temperature line a and the temperature line i, will determine the time required t heat the liquid from 30 degreesto '75 degrees with respect to the temperaturevscale when the temperature of the surrounding atmosphe're is 45 degrees, and that part of the curve between the temperature lines e and g with respect to the temperature scale X will determine the time required to heat the liquid from 65 degrees to '75 degrees when the temperature of the surrounding atmosphere is 45 degrees. Similarly that part of the curve 80 between the temperature lines a and d with respect to the temperature scale Y will determine the time required to heat the liquid from 60 degrees to '75 degrees when the temperature of the surrounding atmosphere is 60 degrees, and that part of the curve 80 between the temperature lines I) and d with respect to the temperature scale Y will determine the timerequired to heat the liquid from 65 degrees to '75 degrees when the temperature of the surrounding atmosphere is 60 degrees. The actual time required to heat the liquid in vessel i from 65 degrees to '75 degrees for different temperatures of the atmosphere surrounding the vessel is illustrated by the hatched bands at the right of and 'ediately adjacent to the curve Figure '7, eac band being labeled with a light circle in which the atmospheric temperature is stated. Obviously and as will be noted from the difierent lengths of the hatched bands, the higher the temperature of the atmosphere surrounding the vessel the less will be the time required to heat the liquid from 65 degrees to '75 degrees.

The curve 8i, Figure '7, represents a cooling curve for the liquid in the vesseh i ,by plotting temperature against time as illustrated, with the assumption that the high point of the curve which coincides with the line 111. is 60 degrees above the low point of the curve which coincides with the line a, and that the line a represents the temperature of the atmosphere surrounding the vessel. For example, curve 8|, Figure '7, repments the rate of coolingof the liquid invessel I with respect to the temperature scale V when the temperature of the atmosphere surroimdin'g the vessel is 15 degrees. It is obviohs that the 0001-' as I of the surrounding atmosphere is 45 degrees the same cooling curve will apply with respect to' the temperature scale X, and if the temperature of the surrounding atmosphere is 60 degrees the curve 5! still applies but with respect to the temperature scale Y. In other words the cooling curve 8! will apply for any atmospheric condition so long as the initial temperature line a'represents the atmospheric temperature.

It therefore follows that ii the temperature of e the atmosphere is 15 degrees and the heater 3 has. beenshut 0E when the temperature of the liquid has reached '75 degrees, the curve ll be- 1 tween the temperature lines m and a will devtermine with respect to the temperature sca1e V the time required for the liquid to radiate from 75 degrees to 15- degrees and that part of the curve between the temperature lines m and k with respectto the scale V will determine the time required for the liquid to radiate from 75 degrees to 65 degrees when the temperature of the surrounding atmosphere is -15 degrees. In like manner, that part of the curve 8| between the temperature line i and the temperature line awilldetermine the time required for the liquid to radiate from 75 degrees to 30 degrees with respect to the temperature scale W when the temperature of the surrounding atmosphere is 30 degrees. Also that part of the curve 8| between the temperature lines h and j with respect to the temperature scale W will determine the time required for the liquid to radiate from 75 degrees.

to 65 degrees when-the temperature of. the surrounding atmosphere is 30 degrees. Again that part of the curve 8| between the temperature lines a and 'a with respect to the temperature scale X will determine the time required for the liquid to radiate from 75 degrees to 45 degrees, and that part of the curve 8| between the temperature-lines g and c with respect to the temperature scale X will determine the time required for the liquid to radiate from 75 degrees to 65' degrees when the temperature of the surrounding atmosphere is 45 degrees. Similarly that part voi! the curve 8| between the temperature lines it and a with respect to the temperature scale Y will-determine the'time'required for the liquid to degrees.

As stated above, the time required to heat the radiate from 75 degrees to 60 degrees when the temperature of the surrounding atmosphere is.

60 degrees, and that part of the curve 8| between the temperature lines d and b with respect to the temperature scale vY will determine the time required for the liquid to radiate from 75 degrees to 65- degrees when the temperature of the surrounding atmosphere is 66 degrees. The actual time required for the liquid in vessel I to radiate from 75 :degreesto 65 degrees for different temperatures' of the atmosphere surrounding the vessel is illustrated by the black bands at the left of and immediately adjacent to the cooling curve 8|. Figure '7, each band being labeled with a heavy circle in which the atmospheric temperature is stated. Obviously and as will be noted from the different lengths of the blackrbands, the .higher the temperature of the atmosphere surrounding the vessel, the longer it will take for the liquid to radiate from liquid from 65 degrees to 75 degrees, and the time requiredfor the liquid to radiate from 75 degrees to 65 degrees, whentthe temperature of the atmosphere is 15 degrees, is represented respectively by the hatched band as and the blaci band 88, said bands being respectively labeled with. alight circle and a heavy circle, in which circles the atmospheric temperature (15) is stated. As soon as the heater 3 has heated the liquid to 75 degrees, the heater 3 and the steam valve ;33, in the manner already stated, will be simultaneously shut oil. This will permit both the building,and the liquid to radiate until the temperature or the liquid reaches 65 degrees, at which time the heater 3 and the valve 33 will, in the manner already stated, again be turned on until the temperature of the liquid again reaches 75 degrees, this cycle repeating itself so long as the temperature of the atmosphere remains 15 degrees Fahrenheit. The consecutive heating 75 degrees to 65 I therefore be represented by the hatched portions 89 of the bandalong the temperature line It, and the consecutive periods during which the valve is'closed may be represented by the black portions 86 of the same band.

Similarly the time required to heat the liquid from 65 degrees to 75 degrees, and the time required for the liquid to radiate from 75 degrees to 65 degrees, when the temperature of the at-- mosphere is '30 degrees, is represented respectively by the hatched band 9| and the black band 82, said bandsbeing, respectively labeled with a light circle and a heavy circle, in which circles the atmospheric temperature (30) is stated. As soon as the heater has heated the liquid to 75 degrees, the heater 3 and the steam valve 33 will, in the manner already stated, be simultaneously the liquid to radiate until the temperature of the liquid reaches 65 degrees at which time the heater 3 and the valve 33. will, in the manner already stated, again be turned on untfl the temperature of the liquid again reaches 75 degrees, this cycle repeating itself so long as the temperature of the atmosphere remains 30 degrees. The consecutive heating and cooling of the liquid in the vessel between the temperatures 75 degrees and 65 deshut off. This will permit both the building and grees, and represented respectively by the curves 83 and the curves 84 with respect to-the temperature scale W, Figure 7, will obviously repeat f themselves so long as the surrounding tempera-' ture of the atmosphere remains 30 degrees. when the temperature of the atmosphereis 30 degrees the consecutive periods during which the valve 83 is open may therefore be represented by the hatched portions 8| of the band along the temperature line 12., and the consecutive periods during which the valve 33 is closed may be represented by the black portions 82 of the same band.

Again the time required to heat the liquid from 65 degrees to 75 degrees, and for the liquid to radiate from 75 degrees to 6 5 degrees when the'temperature of the atmosphere is degrees, is represented respectively by the'hatched band 93 and the black band 94, said bands being respectively labeled with a light circle and a heavy 'circle in which the atmospheric temperature (45) is stated. As soon as the heater 3 has heated the liquid to 75 degrees, the heater and the steam valve 33 will, in the manner already stated, be simultaneously shut oil. This will per-' mit both the building and the liquid to radiate until the temperature or the liquid reaches 65 degrees, at which time the heater 3 and the valve 33 will, in the manner already stated, again be turned on until the temperature of the liquid again'reaches 75 degrees, this cycle repeating itself so long as the temperature of the atmosphere remains 45 degrees. The consecutive heating and cooling of theliquid in the vessel between the temperatures 75 degrees and 65 degrees, and represented respectively by the curves 85 and the curves 88 with respect to the temperature scale X, Figure 7, will obviously repeat themselves so long as the temperature of the surrounding atmosphere remains 45 degrees. Therefore when the temperature of the atmosphere is 45 degrees the consecutive periods during which the valve 33 is open and the consecutive periods during which the valve 33 is closed may beillustrated respectively by the hatched portions 93 and the black portions 94 of the band along thetemp'erature line c with respect to the temperature scale X. Similarly when the temperature of the atmosphere is degrees the consecutive periods during which the valve 33'is open and the consecutive periods during which the valve 33 is closed are shown respectively by the'hatched portions 35 and the black portions 96 of the band along the temperature line b with respect to the temperature scale Y.

It will be noted from the above that the length of the period during which the valve 33 remains open decreases as the temperature of the surrounding atmosphere increases, while the length of the period during which the valve 33 is closed increases as the temperature of the surrounding atmosphere increases. In other words the ratio of the periodduring which the valve is'open to the period during which the valve is closed approaches infinity as the temperature of the atmosphere decreases. For example, if the temperature of the atmosphere'becomes low enough the valve will remain open indefinitely. This will obviously happen when the heater 3 is not capable of raising the temperature of the liquid to 75 degrees under the atmospheric conditions involved. Similarly it will be noted that the length of the period during which the valve 33 remains closed increases as the temperature of thesurrounding atmosphere increases while the period during which the valve 33 remains open decreases as the temperature 0! the surrounding atmosphere increases. In other words t e ratio of the period during which the valve is c osed to the period during which the valve is open approaches in flnity as the temperature of the, atmosphere increases. For example, if the temperature-of the atmosphere becomes high enough the valve will remain closed indefinitely. This will obviously happen when the temperature of the atmosphere is too high topermit the liquid to radiate to a temperature below degrees. The increments between the above ratios as the atmospheric temperatln'e changes will obviously be unlimited, thus providing a definite ratio of the time the valve is open to the time the valve is closed for every definite atmospheric condition to which the vesa sel is subjected. Furthermore said ratio increases as the outside temperature decrease which is as it should be in order to keep the valve open for longer periods as the weather grows colder.

In practice the-correct capacity of the heater 3 and the correct quantity or mass of the liquid or other medium heated by the heater'would be determined by experiment or by calculation to suit a properly designed heating system. In such a case the radiation of heat from the building would be in proper proportion to the radiation from the liquid, and the rate of heat input to the liquid would be in proper proportidn to the rate of heat input to the building to establish the proper ratio between the valves open period and the valves closed period as described in connection with Figure 'l, to maintain an even temperature within the building. It is easily conceived, however, that some buildings may be provided with excessive heating surface for keeping the building warm. In such a case the temperature 0! the building might be kept at too high a temthe rheostat it may be adjusted to increase the.

rate oi: heat input to the heater 3 thereby heat-. ing the liquid at a greater rate. In such a case the heating curve 80 would take the foreshortened form as illustrated in Figure 8. With this particular curve, when the temperature of the atmosphere is 15 degrees the time required to heat the liquid from 65 degrees to degrees w uld' be represented by the hatched portions 89 along the temperature line k with respect to the temperature scale V, which it will be noted is considerably shorter than the same hatched portions 89 illustrated in Figure 7'. It is obvious, however, that the increased rate of heating the liquid 2 will have no effect on the-rate at which this liquid cools when the heat has been turned ofi. The cooling curve M of Figure 8 is therefore the sameas the which the valve is closed will not be affected. In like manner the rheostat It may be adjusted to decrease the rate or heat input to the heater 3 thereby increasing the period during which the valve is open, for any given atmospheric conditionr In such a case the curve will be elongated instead of foreshortened as illustrated in Figure 8. The numerals of both Figures 8 and 7 are identical so tat the previous description with respect to the Figure 7 can be applied to Figure 8. It will thus be noted that in both Figures 7 and 8 the ratio of the time the valve is open to the time the valve is closed decreasesas the atmospheric temperature increases, but by changing the rate of heat input to the heater 3 by means of the rheostat H tlie ratio of the time the valve is open to the time the valve is closed my be increased or decreased proportionately for all atmospheric conditions, depending upon whether the rheostat is turned in one direction or the other. In

order therefore to facilitate adjustmentto establish the proper ratio between the heating of the liquid in the vessel l and the cooling of the liquid in the vessel 8 to suit .a particular building, the rheostat i5 is preferably placed in the chief engineers oflice 63 as illustrated in Figure 6 already reien'ed to.

Another adjustment that can be made with respect to the cm'ves 83 and 8|, Figure '7, is to change the mass or quantity of liquid in the vessell which is heated by the heater 3. This can accomplished for example by a chamber 59, Figure 5, which is slidably mounted on a rod ll alongside of the vessel i, and which can be fastened in any fixed position by means of a set screw 13 which holds the sleeve 12 tightly 4 may communicate with the space in the chamber 69 to establish a common level 75, a vent ll being provided to relieve the air pressure above the liquid in the chamber- 63.. It is obvious that by increasing or decreasing the elevation of the chamber 69 the quantity of liquid in the vessel I.can be varied accordingly. It is further obvious that by increasing the quantity oi liquid in the vessel I both the time required for the heater 3 to heat the liquid in the vessel I and the time for the liquid to. radiate will be increased. Increasing the quantity of liquid in vessel I would thus spread out both the heating curve 80 and .the cooling curve 8|, Figure 7, thereby changing their form to the dotted curves 99 and Hill respectively. Similarly if the quan- Justment therefore in combination with the'ad- Justment provided by means of the rheostat I4 provides means for adjusting the temperature regulation system in question to suit any particular building or to suit any particular climatic condition in order to maintain a specified temperature within very narrow limits within the building itself. It is also obvious that since an adjustment of the rheostat changes the ratio of the period during which the valve is open to --the period during which the valve is closed, this adjustment may not only be used to adiust the system to meet the particular characteristics of the building for the purpose of maintaining a certain temperature within the building, but the adjustment may also be utilized to actually change the flxed temperature which is automatically maintained within the building.

Although I have illustrated and .described mercurial thermometer as the thermostatic element for regulating the heat input to the build- I .ing, it is, obvious that any other suitable form of thermostat or temperature actuated medium may be substituted without in any way departing from this invention: Furthermore any form of heater and any form of mass may be respectively substituted for the electric heater'and the medium under its influence without in any way aflfecting the following claims. Likewise with slight modifications such as required to reverse the action of the motor valve, the same apparatus and methods may be utilized to regulate a cooling I system for maintaining withinnarrow limitsa temperature in a building or chamber below that 01' the surrounding atmosphere.

' It might also be stated that although, for the purpose of description, I have provided a range 01' temperature from degreesto '75 degrees for the temperature scale V, Figures '7 and 8, it

is obvious that the low point of this scale would represent the lowest temperature that might be expected in the particular locality where the control system is used. Furthermore the range of 10 degrees for the temperature .01 the liquid in for simultaneously turning on both' heating means atv a predetermined temperature of the fluid and means for simultaneously turning of! both heating means at a predetermined higher temperature of the fluid.

2. In a device of the class described, the combination with a vessel containing a variable amount of fluid,- oi-meansior heating the fluid, a chamber located apart irom the vessel, means vfor heating the inside of the chamber, thermostatic means in the fluid for simultaneously turning on the fluid heating means and the chamber heating means at a predetermined temperature of the fluid, and thermostatic means in the fluid for simultaneously turning 01! .the fluid heating means and the chamber heating means at a predetermined higher temperature of the- 3. In a device of. the class described, the combination with a -vessel containing a variable amount a! liquid, or means :Ior heating the liquid, thermostatic means for turning on the heating means at a predetermined temperature of the liquid, thermostatic means for turning ofl the heating means at a second predetermined temperature of the liquid, a housing and means .ior regulating the temperature within the housing actuated by said thermostatic means.

4. In a device of the class described, the combination with a building, of means for heating the building, a vessel containing fluid located outside ofthe building, means for heating the fluid, electrical means for simultaneously turning on the building heating means and the iilui dv .heating means, a secon electrical means for simultaneously turning means and the fluid heating means, a mercurial thermometer located in the fluid, a contact wire with which the mercury in the thermometer predetermined higher temperature, an electric circuit which includes the mercury, the flrst contact wire and the flrst electrical meanaand an electriccircuit which includes the mercury, the

the building heating makes electric contact when the fluid reaches a second contact wire and the second electrical means.

5. In a device of the class described, the-combination with a vessel containing a fluid, or means for heating the fluid, means for shutting oi! the heating meansya valve, means for opening the valve, means for clomng the valve, a thermostatic element in the fluid for simultaneously the fluid heating means and theivalve opening means at a predetermined temperature of the fluid and ior simultaneously actuating the shut ting on means and the valve closing means a predetermined higher temperature or the fluid.

6. 'In a device or the class described, the combination with a vessel containing a fluid, of means for heating the fluid, means for shutting oil the heating means, a valve, means for opening the.

valve, means tor closing the valve, an electric circuit 101' simultaneously actuating the fluid heating means and the valve opening means, a second circuit for simultaneously actuating the shutting-oil. means-and the valve closing means,

a thermostatic element, in the fluid tor closing the first circuit at a predetermined temperature bination with a building, of a steam heating system in the building, a valve for supplying steam to the system, automatic means for openon the liquid heating means and actuating the valve opening means at a predetermined temperature of the liquid, and simultaneously tuming oi the liquid heating means and actuating the valve closingmeans at a predetermined higher temperature of the liquid.

8. In a device of the class described, the combination with a switch, of a second switch, a third switch, an electromagnet for closing the first and third switches and opening the second switch when said magnet is energized, means for opening the first and third switches and closing the second switch when the magnet is deenergized, a building, a valve for admitting a hot fluid to heat the building, electrical means for opening the valve, electrical means forclosing the valve, a vessel containing a liquid and located outside of the building, an electric heater for heating the liquidya rheostat for. adjusting the capacity of the heater, a mercurial thermometer consisting of a bulb and capillary tube containing mercury and located in the liquid, a

contact wire for making electric contact with themercury and sealed into the capillary tube at a given distance from the bulb,'a second similar contact wire sealed into the capillary tube at a greater distance from the bulb, a third similar contact wire sealed into the capillary tube at a still greater distance from thebulb, a battery,

a circuit which includes the battery, the valve.

opening means and the second switch, a second circuit which includes the battery, the-heater, the rheostat and the second switch, a third circuit which includes the battery, the valve closing means and the first switch, a fourth circuit which includes the battery, the magnet, the first contact wire, the mercury, the second contact wire and the third switch, and a fifth circuit which includes the battery, the magnet, the first contact wire, the mercury and the third contact wire.

9. Ina device of the class described, the combin'ation with a switch, of a second switch, a third switch, an electro-{magnet for closing the first and third switches and opening the second switch when said magnet is energized, means for opendng the first and third switches and closing the second switch when the magnet is deenergized a building, means for heating, the building, Electrical means for turning on the building heating means, a second electrical means for turningofi the building heating means, a vessel containing a liquid and located outside of the building in contact with atmospheric temperatures and air currents, a cover to protect the vessel'against rain and snow, an electric heater for heating the liquid, a rheostat for adjusting the rate of heat input to the heater, means for adjusting the quantity of liquid in the vessel, a mercurial thermometer located in the liquid and consisting of a bulb and a capillary tube containing mercury, a contact-wire for making electric contact with the mercury and sealed into the capillary tube at a given distance from the bulb, a second similar contact wire seated into the capillary tube at a greater distance from the bulb,

a third similar contact wire sealed into the capillary tube at a still greater distance from the bulb, a source of electric current, a circuit which includes the source, the first electrical means and the second switch, a second circuit which in- I cludes the source, the heater, the rheostat, and

the second switch, a third circuit which includes the source, the second electric means, and the first switch, a fourth circuit which includes the source, the magnet, thefirst contact wire, the

mercury, the second contact wire and the third switch, and a fifth circuit which includes the source, the magnet, the first contact wire, the mercury and the third contact wire.

' 10. In a device ofthe class described, the combination with a building, of a vessel containing a liquid and located outside of the building, of a medium located in the liquid and influenced by the temperature of the liquid, a contact with which the medium makes electrical contact at a predetermined temperature of the liquid, a second contact with which the medium makes electrical contact at a higher predetermined temperature of the liquid, means for heating the building, means for heating the liquid, a switch mecha-;

nism for simultaneously turning on or ofl the building heating means and the liquidheating means, electrical means for actuating the switch mechanism in one direction, a second electrical means for actuating the switch mechanism in the opposite direction, a circuit which includes the first electricalmeans, the medium and the first contact, a circuit which includes the second, electrical means, the medium and the second contact, and aswitch actuated by the second electrical means forshort-circuitin'g the two contacts.

11. A first enclosed space exposed to outdoor atmospheric conditions and means for controlling its temperature, a vessel containing a variable amount of liquid exposed to the same outdoor atmospheric conditions and means for controllingv the temperature of the liquid, means for simultaneously operating both temperature controlling means at a predetermined temperature 01 the liquid andmeans for simultaneously stopping the operation of both temperature controlling means at a difierent predetermined temperature of the liquid. 5

12. A first enclosed space exposed to outdoor atmospheric conditions and means for controlling its temperature, a vessel containiiig liquid exposed to the same outdoor atmospheric conditions and means for controlling the temperature v of the liquid, means associated with the vessel for adjustably varying the volume of the liquid, means for simultaneously operating both temperature controlling means at a predetermined temperature of the liquid and means for simultaneously stopping the operation of both temperature controlling means at a different predetermined temperature of the liquid.

13. A first enclosed space exposed to outdoor atmospheric conditions and means for controlling its temperature, a vessel exposed to the same outdoor atmospheric conditions and having liquid therein, means for controlling the temperature of the liquid, thermostatic means responsive tothe temperature of the liquid for simultaneously operating both temperature controlling means at a predetermined temperature of the liquid and for simultaneously stopping the operation of both temperature controlling means at a difierent predetermined temperature of the liquid and means associated with the vesselfor varying the volume of the liquid.

to I

14. In a device of the class described the combination with a vessel containing a liquid, of means for controlling the temperature of the liquid, means associated with the vessel for adiustably varying the volume of the liquid, a chamber located apart from the vessel, means for controlling the temperature of the chamber, means for simultaneously operating both temperature controlling means at a predetermined temperature oi the liquid, and for simultaneously stop-4 means for controlling the temperature of the chamber, means for simultaneously operating both temperature controlling means at a predetermined temperature or the liquid and for simultaneously stopping operation 01' both temperature controlling means at a different predetermined temperature of the liquid, and adjustable means in the chamber for electrically varying the action'oi the temperature'control means for the liquid.

16. In a device 01' the class described the combination with a building of a-variable liquid mass located outside the building, means for controlling the temperature of the building, means forcontrolling the temperature 01. the liquid'mass,.

and means responsive to the temperature oi the liquid for simultaneously controlling both heat controlling means.

17. In adevice oi the class described the, combination with a building or a liquid mass located outside the building, means for controlling the temperature of the building, means for controlling the temperature of the mass and means responsive to the temperature of the liquid for simultaneously controlling both heat control means, and means for adiustably regulating the volume of the liquid mass.

18. In a device of the class described, the combination with a building,,oi means for heating the building, a casing located outside oi! the build ing, means for heating the casing, electrical means for simultaneously turning on the building heating means and the eating heating means. a second electrical means for simultaneously turning oi the building heating means and the located in the casing, a contact wire with which the, mercury in the thermometer makes electric casing heating means, a mercurial thermometer contact when the casing reaches a predetermined temperature, a second contact wire with which the mercury in-the thermometenmakeselectric contact when the casing reaches a predetermined higher temperature, an electric circuit which includes the mercury, the first contact wire and the first electrical means, and an electric circuit which includes the mercury, the secondcontac wire and the second electrical means. I l

19. In a temperature control system for a building, in combination, a control housing of substantial masslocated outside of the building,

9 heating means to heat the control housing and having suflicient capacity to raise the temperature of the control housing to a predetermined value in cold weather, heating means for the building, means responsive to the temperature of the control housing in control of both of said heating means, and means to varythe effective mass of said control housing.

20. In a temperature control system, in combination, a building, heating means for the building, a control housing of invariable size havingsubstantial mass located outside of the building and subject to the same atmospheric conditions as the building, heating means for the control.

housing having suillcient capacity to raise the temperature of the housing to a desired value during cold weather, means responsive to the temperature 01 the housing in control of both of said heating means for simultaneously operating the same, and means to vary the effective mass of the control housing.

FRITZ FREDERICK UEHLING. 

